Electrical remote-reading positionindicating apparatus



Nov. 11, 1947. A. G. CONRAD E'I 'AL 3 ELECTRICAL REMOTE-READINGPOSITIQN-INDICAT ING APPARATUS Filed Nov, 14, 1944 ./A/l /V7'0P5ALBA-7P7 a CONRAD j a F/P/TZE mum 5 W cue 1M ATTORNE/S Patented Nov. 11,1947 ELECTRICAL REMOTE-READING POSITION- INDICATING APPARATUS Albert G.Conrad, Mount Carmel, and Fritz E. Hiller, Stratford, Conn., assignorsto Manning,

Maxwell & Moore,

Inc.

, Bridgeport, Conn., a

corporation of New Jersey Application November 14, 1944, Serial No.563,432

4 Claims. l

The present invention relates to improvements in position-indicatingapparatus and relates more particularly to improvements in electricalremote-reading position-indicating apparatus, i. e'., positiomindicatingapparatus of the type wherein a transmittingor detecting-portion of theapparatus may be situated at one station or location and electricallyconnected to a receivingor indicating-portion of the apparatus which maybe situated at a difl'erent station or location.

One of the objects of the present invention is to provide a superiorelectrical remote-reading position-indicating apparatus or system whichwill accurately and reliably measure variable conditions existing at onestation and indicate such measurements at a relatively-remote point.

Another object of the present invention is to provide a superiorposition-indicating apparatus of the character referred to which will besubstantially unaffected by wide ranges of temperature-changes to whichthe apparatus may be subjected.

A further object of the present invention is to provide a superiorapparatus of the character referred to having a high degree ofcompactness and freedom from troublesome sliding contact, etc.

Still another object is to provide a simple, reliable and compactdetecting-transmitter unit capable of use in conjunction, with anindicatingunit and characterized by a superior degree of sensitiveness.

With the above and other objects in view, as

- will appear to those skilled in the art from the present disclosure,this invention includes all features in the said disclosure which arenovel over the prior art and which are not claimed in any separateapplication.

In the accompanying drawings, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. l is a schematic view of one form of remote-readingposition-indicating apparatus embodying the present invention andshowing the armature or core of the detecting-transmitter device in itsneutral or intermediate positions;

Fig. 2 is a perspective view of the detecting- I transmitter unit;

Fig. 3 is a diagrammatic showing of the circuit indicated in Fig. 1; and

Fig. 4 is a. perspective view of a substitute form of armature or core.

The structure of Figs. 1, 2 and 3 The particular position-indicatingapparatus illustrated in Figs; 1, 2 and 3 comprises two main units ordevices which may be respectively aptly termed a detecting-transmitterunit generally designated by the reference character I0, and anindicating-receiver unit generally designated by the reference characterII.

The two devices I0 and II above referred to are electricallyinterconnected by complemental linewires I2 and I3 and by aninterconnecting-wire I4. The complemental line-wires I2 and I3 may beconnected to any suitable source of alternating or pulsating currentsuch, for instance, as 400- cycle, 10-volt alternating current.

The detecting-transmitter device I0 includes two opposed cup-shapedbody-members respectively designated by the reference characters I5 andI6 respectively having flange-portions I1 and I8 and respectively havingend-walls I9 and 20, which latter are located at the respective oppositeends of the assembly.

The opposed inner ends of the flange-portions I1 and I8 are respectivelyseated against shouldered opposite faces of a disk-like intermediatewall-member 2I, which latter in a manner as will hereinafter appear,serves to provide two magnetic paths. The end-wall I9 of the bodymemberI5 is formed with an axial passage 22 corresponding in size to andlocated in axial alignment with a similar passage 23 formed in theend-wall 20 of the body-member I6. The intermediate wall-member 2| isalso formed with an axial passage 24 which corresponds in size to and islocated in axial alignment with the passages 22 and 23 just referred to.

Mounted for axial reciprocation in the interior of the assembly and inthe respective axial passages 22, 23 and 24 of the elements I5, I6 and2|, is a core-like armature '25. The said armature 25 freely fits thepassages 22, 23 and 24 so as to readily reciprocate therein and isprovided with a rigid operating-rod 26 by means of which the saidarmature may be moved axially with respect to the remainder of thedetecting-transmitter device Ill. The operating-rod 26 may be connectedto any device or apparatus, the position or movement of which it isdesired to indicate by means of the indicating-receiver device II or itsequivalent.

The elements I5, I6, 2| and 25, before referred to, are preferablyformed of powdered iron in order to minimize the effects of eddycurrents, though the said parts may be formed from laminated steel oriron, if desired.

In the instance shown, the outer end of the operating-rod 26 isconnected to one flexible on Q diaphragm-like wall 21 of an expansiblepressurechamber 28, which latter also includes a comple mental flexiblediaphragm-like wall 29. .The two walls or diaphragms 21 and 29 aresecured together adjacent their outer edges and the said wall 29 iscentrally apertured and has an axiallyextending tubular sleeve 30rigidly projecting therefrom. The said sleeve 30 may be connected to atube or pipe 3I leading from any suitable source of fluid, the pressureof which it is desired to measure or indicate.

Mounted within the flange-portion I1 of the body-member I5 intermediatethe end-wall I9 and the intermediate wall-member 2|, is a primary-coil32 and a complemental secondarycoil 33, both of ring-like form andmounted upon a common tubular sleeve or bushing 34. The bushing 34 hasan internal diameter sufficient to freely clear the armature 25.

Mounted within the flange-portion I8 f the body-member I6 in a positionintermediate the end-wall 20 and the intermediate wall-member 2I, is asecondary-coil 35 and a complemental primary-coil 36 jointly mountedupon a sleeve or bushing 31. The said sleeve or bushing, like the sleeveor bushing 34, has an internal diameter sufficient to permit the freeaxial movement of the armature 25.

Both of the primary-coils 32 and 36 and both of the secondary-coils 33and 35 are arranged coaxially so that the core-like armature 25 may bemoved axially through all thereof.

One end of the primary-coil 32 is provided with a terminal 38 to whichis connected the adjacent end of the line-wire I3. The opposite end ofthe primary-coil 32 is connected by a wire 39 to one end of theprimary-coil 36. The remaining end of the primary-coil 36 extends to aterminal 40 to which is connected the adjacent end of the line-wire I2.

The secondary-coil 35 has one end provided with a terminal 4| to whichis connected the adjacent end of the interconnecting-wire I4 beforereferred to. The opposite end of the secondarycoil 35 is connected toone end of the other secondary-coil 33 by means of a wire 42. Theremaining end of the secondary-coil 33 is connected by means of a wire43 to the wire 39 which serves to interconnect the primary-coils 32 and36.

From the foregoing it will be seen that the primary-coils 32 and 36 areconnected in series with each other and with the line-wires I2 and I3.It will also be seen that the two secondary-coils 33 and 35 areconnected in series with each other between the interconnecting-wire I4and a point in the circuit intermediate the two primary-coils 32 and 36(the wire 39). The two secondarycoils 33 and 35 are so connected thattheir respective voltages are opposing, while the respective voltages ofthe primary-coils 32 and 36 are in the same direction. The voltagerelationships just referred to are indicated by the arrows in Fig. 3.

As thus constructed and arranged, the bodymember I in conjunction withthe intermediate wall-member 2 I provides a magnetic path for the fluxdeveloped by the primary-coil 32 and the secondary-coil 33, as indicatedby the arrows 44 which indicate the flux-direction for a given halfcycleof alternating current. Similarly, the bodymember in conjunction withthe intermediate wall-member 2 I, provides a path for the magnetic fluxdeveloped by the primary-coil 36 and its complemental secondary-coil 35,as indicated by the arrows 45 for a given half-cycle of alternatingcurrent occurring at the same instant as prevlous'ly described inconnection with the primarycoil 32 andsecondary-coil 33.

The indicating-receiver or motion-indicating device I I may be in theform of any suitable ratiometer and in the instance shown includes twocomplemental coils 46 and 41. The respective inner terminals of thecoils 46 and 41 are connected to the interconnecting-wire I4, w hile therespective outer ends of the coils 46 are respectively connected to theline-wires I2 and I3.

The indicating-receiver device or motion-.ndicating device II alsoincludes an armature 48 carried at the inner end of a lever 49. The saidlever is pivoted intermediate its respective opposite ends as at 50 andis provided at its outer end with a pointer 5I adapted to sweep oversuitable indicia, printed or otherwise applied to the surface of adial-plate 52.

The construction and arrangement of the parts of the unit II are suchthat the armature 48 assumes a position such that the forces exerted onit by the coils 46 and 41 are equal and opposite. Hence a change in theratio between the respective currents flowing through the respectivecoils 46 and 41 will cause corresponding changes in the opposing forcesacting on the armature 48 and thus cause a change in the position ofboth the said armature and the pointer 5|.

Operation When the armature 25 is in the intermediate position in whichit is shown in Fig. 1 of the drawings, the respective reluctances of thefluxpaths represented by the arrows 44 and 45 are equal and hence thevoltages across the respective coils 46 and 41 of theindicating-receiver unit II will be equal. Under these circumstances,the pointer 5I will assume substantially the position in which it isshown in Fig. 1.

For purposes of description, let it now be assumed that the core-likearmature 25 is moved downwardly from the position in which it is shownin Fig. 1 of the drawings. Under these conditions, the reluctance of theflux-path represented by the arrows 44 will increase, whereas thereluctance of the flux-path represented by the arrows 45 willcorrespondingly decrease.

With the cores shifted downwardly as above referred to, there will be anincrease in the voltage applied across the primary-coil 36 and anincrease in the voltage induced in the complemental secondary-coil 35.coincidentally, there will be a reduction in the voltage applied acrossthe primary-coil 32 and a decrease in the voltage induced in itscomplemental secondary-coil 33. These respective increases and decreasesas just above described, will be a function of the position attained bythe said armature 25.

The voltage increases above referred to in connection with the coils 36and 35 will cause an increase in the voltage applied across the coil 46of the indicating-receiver unit II, while the coincidental decrease inthe voltages appearing across the coils 32 and 33 will cause acorresponding reduction in the voltage applied across the coil 41 of theunit II.

The above-described changes in voltages applied across the respectivecoils 46 and 41 will cause the pointer 5| to be deflected in a clockwisedirection as viewed in the drawings. The degree of movement of thepointer 5|, will, of course, be a function of the degree of movementimparted to the armature 25.

Should the armature 25 be moved upwardly to a position above theposition in which it is shown in Fig. 1, the reluctance of the flux-pathrepresented by the arrows 44 will be decreased, while the reluctance ofthe flux-path represented by the arrows 45 will be correspondinglyincreased. In

this manner, the voltage applied across the primary-coil 32 will beincreased, as will also the voltage induced in the secondary-coil 33.Coincidentally, the voltage applied across the primary-coil 36 will bedecreased and the i duced voltage in the secondary-coil 35 will 'bedecreased. Under these circumstances, the voltage applied across thecoil 41 of the unit I I will be increased. while the voltage appliedacross the opposite coil 46 of the said unit will be decreased. Underthese latter conditions, the pointer 5| will be deflected in acounterclockwise direction to a degree which will be a function of thedegree to which the armature 25 has been shifted upwardly beyond itsintermediate position.

From the foregoing it will be seen that the position of the pointer 5|at any given time depends upon the position of the armature 25 at suchtime. Any shift in the position of the said armature 25 will cause aproportionate shift in the position of the pointer 5| or its equivalent.

From the foregoing it will also be seen that any change in the positionof the core-like armature 25 will occasion a voltage-change across eachof the coils 32, 33, 35 and 36. The integrated effect of the fourvoltage-changes just referred to will be evidenced by the change in theposition of the pointer 5|.

Attention is further called to the fact that in the embodiment of theinvention herein shown, each primary-coil and its complementalsecondary-coil are provided with independent ,fiuxpaths. Thus, theprimary-coil 32 and its complemental secondary-coil 33 may have the fluxpath 4, while the primary-coil 36 and its complemental secondary-coil 35are provided with the flux-path 45. It is preferred and as shown in Fig.1, that the coils be 50 arranged that the flow of flux through theintermediate wall-member 2| is in the same direction at any giveninstant to thus avoid having the flux in one flux-path buck the flux inthe other flux-path. i

The armature of Fig. 4

Instead of employing an armature such as 25 "formed throughout itslength of magnetic material, an armature such as is shown in Fig. 4 maybe employed.

The armature referred to consists of two opposite end-portions 53 and 54formed of sintered iron or other suitable magnetic material, and rigidlyconnected together by a non-magnetic spacer 55 formed of any suitablenon-magnetic material. The respective lengths of the endportions 53 and54 are such as to enable them to respectively discharge the function offorming parts of the flux-paths and 45 indicated in Fig. 1.

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit and essentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

We claim:

1. A detecting-transmitter unit for remotereading position-indicatingapparatus, including in combination: a pair of primary-coils connectedin series with each other and each having a terminal constructed andarranged for connection to an electrical indicating-device; a pair ofsecondary-coils respectively located adjacent to and in the field of oneof the two said primarycoils and electrically connected together so thatthe voltage induced in one thereof is in opposition to that induced inthe other, each of the said secondary-coils having a terminal oppositeits point of connection to the other secondary-coil, the terminal of oneof the said secondary-coils being connected to the junction between thetwo said primary-coils, and the terminal of the other secondary-coilbeing constructed and arranged for connection to an electricalindicating-device; an armature-member having a portion movable in thefield of one of the said primary-coils and its complementalsecondary-coil, the said armature-member also having a portion movablein the field of the other of said primary-coils and its complementalsecondary-coil; and flux-conducting means formed of magnetic materialand constructed and arranged in conjunction with the respective portionsof the said armaturemember to provide two distinct flux-pathsrespectively extending around one of the said pri mary-coils and itsadjacent complemental secondary-coil.

2. A detecting-transmitter unit for remotereading position-indicatingapparatus, including in combination: a pair of substantiallyconcentrically-arranged ring-like primary-coils connected in series witheach other and each having a terminal constructed and arranged forconnection to an electrical indicating-device; a pair of ring-likesecondary-coils substantially concentric with the said pair ofprimary-coils and respectively located adjacent to and in the field ofone of the two said primary-coils, the said pair of secondary-coilsbeing electrically connected together so that the voltage induced in onethereof is in opposition to that induced in the other, each of saidsecondary-coils having a terminal opposite its point of connection tothe other secondary-coil, the terminal of one of the saidsecondary-coils being connected to the junction between the two saidprimary-coils, and the terminal of the other secondary-coil beingconstructed and arranged for connection to an electricalindicating-device; a bar-like armature-member having a portion movablelongitudinally in the field of one of the said primarycoils and itscomplemental secondary-coil, the said armature-member also having aportion movable longitudinally in the field of the other of saidprimary-coils and its complemental secondary-coil; and flux-conductingmeans formed of magnetic material and constructed and arranged inconjunction with the respective porpair of secondary-coils beingelectrically connected together so that the voltage induced in onethereof is in opposition to that induced in the other, each of the said"secondary-coils having a terminal opposite its point of connection tothe other secondary-coil, the terminal of one of the saidsecondary-coils being connected to the junction between the two saidprimary-coils, and the terminal of the other secondary-coil beingconstructed and arranged for connection to an electrical indicatingdevice; a bar-like armature-member having a portion movablelongitudinally in the field of one of the said primary-coils and itscomplemental secondarycoil, the said armature-member also having aportion movable longitudinally in the field of the other of saidprimary-coils and its complemental secondary-coil; and a casing formedof magnetic material and constructed and arranged in conjunction withthe respective portions of the said armature-member to provide twodistinct fiuxpaths respectively extending around one of the saidprimary-coils and its adjacent complemental secondary-coil.

4. A detecting-transmitter unit for remote reading position-indicatingapparatus, including in combination: a pair of substantiallyconcentrically-arranged ring-like primary-coils connected in series witheach other and each having a terminal constructed and arranged forconnection to an electrical indicating-device; a pair of ring-likesecondary-coils substantially concentric with the said pair ofprimary-coils and respectively located adjacent to and in the field ofone of the two said primary-coils, the said pair of secondary-coilsbeing electrically connected together so that the voltage induced in onethereof is in opposition to that induced in the other, each of the saidsecondary-coils having a terminal opposite its point of connection tothe other secondary-coil, the terminal of one of the saidsecondary-coils being connected to the junction between the two saidprimary-coils,

and the terminal of the other secondary-coil being constructed andarranged for connection to an electrical indicating-device; a bar-likearmature-member having a portion movable longitudinally in the field ofone of the said primarycoils and its complemental secondary-coil, thesaid armature-member also having a portion movable longitudinally in thefield of the other of said primary-coils and its complementalsecondary-coil; and a casing formed of magnetic material and envelopingthe said primary-coils and the said secondary-coils, the said casingbeing formed with two end-walls extending radially inwardly intoproximity to the said armature-member and also provided intermediate itsrespective opposite ends with an intermediate wall extending radiallyinwardly into proximity to the said armature-member and located betweenone of the said primary-coils and its complemental secondary-coil on theone hand and the other of the said primary-coils and its complementalsecondary-coil on the other hand.

ALBERT G. CONRAD. FRITZ E. HILLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain Feb. 3, 1936

